Molalno

Molalno is a linguistic term used in several South Slavic languages to denote something relating to molality, a concentration measure in chemistry. In practice, molalno is used to describe quantities, properties or discussions that are expressed in terms of molality rather than other concentration units.

Molality, symbolized as m, is defined as the amount of solute in moles divided by the mass of solvent in kilograms. The unit is mol/kg. A solution described as 1 m has one mole of solute per kilogram of solvent. Unlike molarity, which uses volume, molality relies on mass and is therefore less sensitive to temperature-induced volume changes.

Molalno usage commonly appears when discussing how solvent quantity affects solution behavior. For example, colligative properties such as boiling-point elevation and freezing-point depression depend on the molality of the solute particles, not on the total volume. The freezing-point depression ∆Tf and boiling-point elevation ∆Tb can be expressed as ∆Tf = i·Kf·m and ∆Tb = i·Kb·m, where i is the van’t Hoff factor and Kf and Kb are constants for the solvent.

Relation to molarity is not direct, because molarity (mol/L) depends on solution volume, which changes with temperature and composition. Converting between molality and molarity requires knowledge of the solution’s density and the solute’s and solvent’s masses.

In sum, molalno describes concepts tied to molality, a robust concentration measure for temperature-insensitive analyses and discussions of colligative properties.